Hippoglossus stenolepis
Hippoglossus stenolepis (''Pacific halibut)' Kingdom: '''Animalia Phylum: Chordata Class: Actinopterygii Order: Pleuronectiformes Family: Pleuronectidae Genus: Hippoglossus Species: Hippoglossus stenolepis Environment: milieu, climate zone, depth range, distribution range: Marine; demersal; oceanodromous; depth range 0 - 1200 m. Temperate; 73°N - 42°N, 138°E - 123°W. Distribution: North Pacific: Hokkaido, Japan and the Sea of Okhotsk to the southern Chukchi Sea and Point Camalu, Baja California, Mexico. Size, weight, age: Max. length: 2.58 m (male), 2.67 m (female); weight: 363 kg; age: 55 years Short description: Pacific halibut have diamond-shaped bodies. They are more elongated than most flatfishes, the width being about one-third of the length. It has a high arch in the lateral line over the pectoral fin, and a lunate, or crescent-shaped tail, which is different from other flat fishes. Small scales are embedded in the skin. Halibut have both eyes on their dark upper side. The color on the dark side varies, but tends to assume the coloration of the ocean bottom. The underside is lighter, appearing more like the sky from below. This color adaptation allows halibut to avoid detection by both prey and predator. They are one of the largest flatfish (only surpassed by the closely related Atlantic halibut), and can weigh up to 500 lb (230 kg) and grow to over 8 ft (2.4 m) long. Biology: Found on various types of bottoms. Young are found near shore, moving out to deeper waters as they grow older. Older individuals typically move from deeper water along the edge of the continental shelf where they spend the winter, to shallow coastal water for the summer. Feed on fishes, crabs, clams, squids, and other invertebrates. Utilized fresh, dried or salted, smoked and frozen; eaten steamed, fried, broiled, boiled, microwaved and baked. Life cycle and mating behavior: Spawning takes place during the winter months, with the peak of activity occurring from December through February. Most spawning takes place off the edge of the continental shelf in deep waters of 600 to 1,500 ft (183 to 457 m). Male halibut become sexually mature at seven to eight years of age, while females attain sexual maturity at eight to 12 years. Females lay 0.5 to 4.0 million eggs annually, depending on the size of the fish. Fertilized eggs hatch after about 15 days. Free-floating larvae float for up to six months and can be transported several hundred miles counter-clockwise by North Pacific currents. During the free-floating stage, many changes take place in the young halibut, including the movement of the left eye to the right side of the fish. During this time, the young halibut rise to the surface and are carried to shallower water by prevailing currents. At six months, the halibut has its adult form and is about 1.4 in (3.6 cm) long. In the shallower water, young halibut then begin life as bottom dwellers. Most young halibut ultimately spend from five to seven years in rich, shallow nursery grounds such as the Bering Sea. Young halibut are highly migratory and generally migrate in a clockwise direction east and south throughout the Gulf of Alaska. Halibut in older age classes tend to be less migratory, but continue to move predominately on a clockwise direction. Mature fish are also involved in winter spawning migrations towards deeper waters, migrating across several areas in some instances. Research has indicated small, localized spawning populations may occur in deep waters such as in Chatham Straight in northern Southeast Alaska. However, because of the free-floating nature of larvae and subsequent mixing of juvenile halibut from throughout the Gulf of Alaska, only one genetic stock of halibut is known in the northern Pacific. Halibut growth rates vary depending on locations and habitat conditions, but females grow faster than males. The oldest recorded female and male were 55 years old. The largest recorded sport-caught halibut was 459 lb (208 kg) near Unalaska, AK, in 1996. Main reference: Eschmeyer, W.N., E.S. Herald and H. Hammann, 1983. A field guide to Pacific coast fishes of North America. Boston (MA, USA): Houghton Mifflin Company. xii+336 p. IUCN Red List Status: Not Evaluated CITES: Not Evaluated CMS: Not Evaluated Threat to humans: Harmless Human uses: Fisheries: highly commercial; gamefish: yes; aquarium: public aquariums. Category:Pleuronectidae, Righteye flounders